The subject matter disclosed herein relates to a rotating component of a turbine engine and, more particularly, to an impeller with a saw cut design to improve durability.
In gas turbine engines, high energy and high temperature fluids are provided to a turbine where the fluids are expanded for the production of mechanical and electrical energy. This fluid expansion is facilitated by various rotating components that rotate about a common rotational axis.
The rotating components include, for example, an impeller wheel that is rotatable about the rotational axis with impeller vanes provided on a face thereof. The impeller vanes direct secondary flow from an outer turbine diameter to an inner turbine diameter. During transient operations of the turbine, however, the impeller vanes are exposed conditions that cause them to heat and cool relatively quick. This causes high thermal gradient across the impeller wheel, which leads to development of high thermal stresses at the inner diameter of the impeller wheel (this includes both compressive stresses experienced during start-up and tensile stresses experienced during shut down). These mechanical stresses due to speed and gas loads and thermal stresses interact at common locations and cause damage that reduces the impeller wheel's fatigue life.